Oil separator for engine crankcase ventilation system



A. E. KOLBE Dec. 8, 1959 OIL SEPARATOR FOR ENGINE CRANKCASE VENTILATION SYSTEM Filed Dec. 12, 1958 M Mg M 4. w

m-ToRA/Ey United States Patent OIL SEPARATOR FOR ENGINE CRANKCASE VENTILATION SYSTEM Adelbert E. Kolbe, Berkley, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application December 12, 1958, Serial No. 779,982

3 Claims. (Cl. 121-194) The invention relates to a crankcase ventilating system for an internal combustion system and more particularly to an oil separator for separating oil suspended in crankcase fumes prior to their exhaust to the atmosphere.

The crankcase of an engine must be connected to the atmosphere in order to prevent an undue build-up of pressure and explosive vapors while the engine is running. The fumes or vapors found in an engine crankcase include a portion of the engine lubricating oil either as a vapor or in droplets suspended in the fumes. In order to prevent undue oil consumption, it is desirable to recover the oil so suspended before permitting the crankcase vapors to be exhausted to the atmosphere. While separators having such purposes have been previously provided, they have been commonly mounted within the crankcase of the engine block. This installation requires them to be installed while the engine oil pan is removed and results in a considerable amount of unnecessary work when the separator must be replaced.

The separator embodying the invention is particularly adapted to be installed on the outside of the engine block while still returning the separated oil to the engine crankcase. The separator is secured in sealed relation to the outer wall of the engine block and provides a series of flow reversing passages through which the crankcase fumes pass in order to condense and separate the oil therefrom. The separator provides oil flow openings by which all of the oil so operated may be returned to the crankcase without being entrained in the fumes and carried out through the ventilation pipe. It permits greater oil condensation by providing cooler condensing surfaces. The system also provides a simplified mounting for the separator and vent tube.

In the drawing:

Figure 1 is an end view of a portion of an internal combustion engine having an oil separator embodying the invention installed and showing parts broken away and in section.

Figure 2 is an enlarged view of the oil separator of Figure 1 with parts broken away and in section.

The engine includes an engine block 12 to which an oil pan 14 is secured to provide an engine crankcase cavity 16 and an oil sump. A boss 18 extends out of the wall portion 20 of the engine block at a slightly upward angle. The boss is provided with a recess 22 which receives the oil separator 24. A perforated web 26 is provided across the opening 28 formed in boss 18. The central portion of web 26 may be drilled and tapped to receive the oil separator and ventilation pipe mounting bolt 30.

The oil separator 24 has the ventilation pipe 32 secured to the outlet end of the separator by the bolt 30 so that the pipe may extend downwardly and rearwardly to discharge the crankcase vapors in the well known manner. The ventilation system thus has all of its exterior components fastened in place for easy removal and replacement.

Oil separator 24 has a base 34 which fits within recess 22 of boss 18 and is provided with a seal or gasket 36 to seal the opening 28. The oil separator has an outer shell 38 which is cup-shaped and flanged at 40 so that base 34 may be cn'mped over the flange and secured thereto. The outer shell 38 includes a generally circular side wall 42 and an end wall 44. End wall 44 is provided with an aperture 46 through which the outlet tube 48 extends from the ventilation pipe 32 into the oil separator. The separator is provided with an inner shell 50 which is concentric with side wall 42 of shell 38 and received therein. Shell 50 is secured to base 34 by several radially extending mounting tabs 52 which hold the shell in spaced relation to the base 34 to provide arcuate openings 54, one of which is positioned at the lowest part of the inner shell 50 when the separator is in the installed position. Outlet tube 48 extends concentrically within the inner shell 50 and terminates at a substantial distance from base 34. Side wall 42 and inner shell 50 define an annular passage 58 which is connected with arcuate openings 56 formed in base 34. These openings are substantially as wide as passage 58 and provide an entry to the separator for the crankcase vapors. Inner shell 58 and outer shell 38 also define a reversing passage 60 in cooperation with the outlet tube 48. Outlet tube 48 and inner shell 50 define another annular passage 62 and, in cooperation with base 34, define a second reversing passage 64 which leads to the inner passage 66 of outlet tube 48.

Oil laden crankcase vapors move to the upper portion of the crankcase cavity 16 and pass through arcuate openings 56 and into annular passage 58. Some of the oil in the vapors is condensed or separated against the surface of the base 34 and drops back into the pan 14. The vapors continue through passage 58 and are in contact with the relatively cool outer shell side wall 42 which further causes condensation of the oil. Oil condensed on the surfaces of side wall 42 and inner shell 50 will flow downwardly under influence of gravity and return to the crankcase through arcuate openings 56. The vapors continue through reversing passage 60. This change in direction of flow causes more of the oil to be separated against shell 38 and return to the crankcase. The vapors then pass through annular passage 62 and through the second reversing passage 64 and out through passage 66 of tube 48. Each change of direction of the vapors causes more oil to be condensed or separated from the vapors. The oil condensed on the inner surface of inner shell 50 and base 34 will flow downwardly through the small arcuate openings 54 and into the crankcase cavity 16 through the arcuate openings 56 formed in the separator base.

A simple and compact oil separator has thus been provided which may be readily installed externally of the internal combustion engine. The separator will separate and condense oil entrained in crankcase vapors and return it to the crankcase cavity. By locating the oil separator outside the engine crankcase, a cooler separator is provided which will tend to more thoroughly condense oil held in the impinging crankcase vapors. This advantage is obtained by exposing the separator outer shell 38 directly to the cool air circulating through the engine compartment of the engine installation.

What is claimed is:

1. In an engine crankcase ventilation system, an oil separator mounted exteriorly of the engine crankcase and a ventilation drafit tube connecting said separator with the atmosphere, said separator being comprised of a base having arcuately formed openings therein and an outer shell having an end wall and a side Wall sealingly secured to said base and an inner shell concentric with said outer shell side wall and secured to said base to provide small spaced drain openings and defining an annular passage therebetween and connecting with said base arcuate passages and inwardly spaced from said outer shell end wall to define a first reversing passage, said tube extending through said end wall concentrically within said inner shell and terminating short of said base and cooperating with said inner wall and said base to define a second annular passage and a second reversing passage, whereby oil-laden vapor entering said base openings passes through said passages and the oil is condensed or separated out and drains out of said separator and into the engine crankcase.

2. An oil separator for an engine crankcase ventilation system comprised of a base having a series of armately extending openings therein and a plurality of shells secured to said base and defining a series of reversing passages for condensing and separating oilfrom crankcase vapors and exhausting the vapors remaining, all of said shells other than the outer shell having edge sections spaced from said base: to provide oil drain openings for returning the separated oil through said arcuately extending openings to said crankcase under gravitational force.

3. The separator of claim 2, said base being sealingly secured to the exterior of the engine crankcase and said shell extending upwardly and outwardly therefrom.

'Edwards June 27,1933 Scheiterlein' Jan. 28, 1958 

